Several infections and diseases in poultry are caused by pathogenic bacteria, including E. coli, Clostridium, and Salmonella. Infections and diseases caused by pathogens result in increased mortality, decreased performance, and increased cost of turkey production. In addition, many of these pathogens can be transmitted to humans.
Avian colibacillosis is a systemic infection caused by E. coli and occurs most commonly in young broilers and poults. Avian pathogenic E. coli (APEC) comprise a specific subset of pathogenic E. coli that cause extraintestinal diseases of poultry. (Snoeyenbos, G. H., et al. 1977 Avain Diseases. 22:273-287.) APEC consists mainly of enteropathogenic E. coli (EPEC) and enterotoxigenic E. coli (ETEC) serovars, i.e., subdivisions of a species or subspecies distinguishable from other strains therein on the basis of antigenicity. (Wiard, T., et al. 2003. Poult. Sci. Asso. Supplement 1:58-59.) APEC is found in the intestinal microflora of healthy birds and infections are enhanced or initiated by secondary environmental and host predisposing factors. Colibacillosis is a common systemic infection caused by APEC, and occurs most commonly as acute septicemia or subacute aerosacculitis and polyserositis in chickens, turkeys, and other avian species (Zhu, X. Y., et al. 2002. Appl. Environ. Microbiol. 68:124-137.).
Clostridium affecting poultry include C. perfringens, C. septicum, and C. botulinum which are anaerobic, gram-positive, spore-forming rods that produce potent toxins. Gangrenous dermatitis and cellulitis have reemerged recently as a significant concern for poultry producers in the U.S. Characterized by necrosis of the skin, subcutaneous tissue, and often the underlying musculature, the disease occurs suddenly and progresses rapidly with death occurring often before the first symptoms are observed. Crepitus tissue caused by gas accumulation under the affected skin is also commonly observed in cases of GD and cellulitis. The anaerobic, spore-forming, gram-positive rod Clostridium has been implicated in numerous cases of necrotizing soft-tissue infections in poultry (Carr, D., et al. 1996. Avian Dis 40:736-41; Hofacre, C. L., et al. 1986. Avian Dis 30:620-2; Willoughby, D. H., et al. 1996. J Vet Diagn Invest 8:259-61). The two most commonly isolated species have been C. perfringens and C. septicum. C. perfringens is ubiquitous in nature, commonly found in the soil and gastrointestinal tracts of warm blooded animals. It produces α-toxin and θ-toxin that work synergistically to produce the pathology observed in C. perfringens associated clostridial myonecrosis (Awad, M. M., et al. 2001. Infect Immun 69:7904-10.). C. septicum is a very virulent, but poorly understood pathogen that is recognized as the causative agent of atraumatic myonecrosis. It also produces α-toxin, distinct from C. perfringens, which acts as a pore-forming cytolysin and is essential for virulence (Kennedy, C. L., et al. 2005. Mol Microbiol 57:1357-66.). In order to better understand the etiology of this disease and the diversity of the Clostridium implicated, microbiological analysis of affected birds' organs and tissues was performed. The results suggest a clostridial bacteremia present prior to death with both species and multiple strains involved.
The spores of C. botulinum are heat-resistant and can survive in foods that are incorrectly or minimally processed. Food borne botulism (as distinct from wound botulism and infant botulism) is a severe type of food poisoning caused by the ingestion of foods containing the potent neurotoxin formed during growth of the organism. The toxin is heat labile and can be destroyed if heated at 80° C. for 10 minutes or longer. The incidence of the disease is low, but the disease is of considerable concern because of its high mortality rate if not treated immediately and properly. Most of the 10 to 30 outbreaks that are reported annually in the United States are associated with inadequately processed, home-canned foods, but occasionally commercially produced foods have been involved in outbreaks.
Strains of Salmonella cause Salmonellosis, which occurs in animals, including humans. It is an enteric disease of varying severity, usually involving diarrhea. With poultry, however, most Salmonella infections are symptomless. Many strains of Salmonella are zoonotic agents, spreading to humans from contaminated food products. In humans, Salmonellosis is one of the most common causes of food poisoning.
Thus, pathogenic bacteria are a major problem for poultry producers. Further complicating this situation is the fact that pathogen populations in poultry production facilities typically fluctuate in terms of both levels and types of pathogens, making control of the pathogens difficult. An adequate disease prevention program is essential to a profitable commercial poultry operation. Chronic diseases can reduce efficiency and increase costs.
To prevent disease in and stimulate growth of turkeys, antibiotics have been used. Fed at a sub-therapeutic level, antibiotics have been found to have beneficial effects. For example, antibiotics reduce levels of lactic acid bacteria, which in adult animals are not needed and can be problematic. In addition, antibiotics increase low G+C, gram positive bacteria, including beneficial Clostridium. See, e.g. WO 2004/104175 to Lee, M. D. et al.
However, there are many drawbacks associated with antibiotic use, such as consumer acceptance and selection of resistant bacteria. For instance, mounting scientific evidence shows that using antibiotics in livestock feed can lead to antibiotic-resistant bacteria that can be transferred to people, making it harder to treat certain infections.
Concerns over antibiotics have led the European Union on Jan. 1, 2006 to ban the feeding of all antibiotics and related drugs to livestock for growth promotion purposes. The sweeping new policy follows up a 1998 ban on the feeding of antibiotics that are valuable in human medicine to livestock for growth promotion. Now, no antibiotics can be used in European livestock for growth promotion purposes.
In the United States, a bill banning low-level feeding of seven antimicrobials (bacitracin, erythromycin, lincomycin, penicillin, tetracycline, tylosin, and virginiamycin) was introduced into the House of Representatives in November 1999 (H.R. 3266).
Accordingly, there is a recognized need for alternatives, such as microorganisms and methods of using microorganism for treating or preventing disease in poultry. Furthermore, there is an important need for improving performance in and health of poultry.